Method of forming and conditioning composite printing plates and the like



July 4, 1944. A. E. LUNDBYE 2,352,905 METHOD OF FORMING AND CONDITIONING COMPOSITE PRINTING PLATES AND THE LIKE Filed June 18. 1942 .Zeddase (a er M Patented July 4, 1944 METHOD F FORMING AND CONDITIDNING COMPOSITE PRINTING PLATES AND THE LIKE Axel E. Lundbye, Springfield, Ohio, assignor to The Crowell-Collier Publishing Company,

Springfield, Ohio, a corporation o! Delaware Application June 1s, 1942, serial No. '447,583

Claims.

My invention relates to a new and novel meth od in the formation and conditioning of printing plates and the like.

As is well known to those skilled in the art. these composite printing plates are made either in flat or circular form and are made up b y pressing the original copper etched plate against a wax or lead mold, after which the mold is placed in a tank so that a coating of nickel may be electrolytically deposited on the mold.

After the nickel has been deposited, a copper coating is electrolytically deposited on the nickel to strengthen the same. The mold with its nickel and copper deposit is then withdrawn from the electrolytic bath and the lead or wax mold stripped away, leaving the nickel and copper plate with the impressions formed thereon.-A

Before the base metal or electrolyte metal, as it is called, which is an alloy of lead, tin and antimony, is cast on the copper surface of the plate, it has been necessary heretofore to place a coating of tinfoil on the copper surface so that when the plate is in the casting machine and the base metal cast thereon-that is, the lead, tin and antimony, it; will adhere to the tinned copper surface of the plate.

One of the objects of the present invention, therefore, is to subject the nickel copper plate to a bath before placing the plate in the casting machine, so that it will be unnecessary to utilize the tinfoil, the bath depositing a thin film or flux on the copper, so that the lead, antimony and tin will adhere thereto, thus dispensing with the tinfoil and its tinning action.

Still another object of the invention is to eliminate the tinfoil that has usually been used in the manufacture of, these plates, and at the same time provide a plate that is just as strong and serviceable as if tinfoil were used.

With these and other objects in view, the invention consists in the new and novel steps hereinafter pointed out.

Referring now to the drawing showing diagrammatically the preferred form in which way the method is carried out,

Fig. 1 shows the master copper etched plate after forming the impressions in the lead mold;

Fig. 2 shows the plate in the electrolytic bath after having the nickel and copper coatings electrolytically deposited thereon (greatly enlarged) Fig. 3 shows the plate with the lead mold stripped away showing the plate now composed of the nickel and copper, and showing the plate in the ux bath; and

Fig. 4 shows the plate in the casting machine and the lead base as having been -applied thereto. It will be understood at the start that the thickness of the various metals has been greatly exaggerated for the sake of clearness of illustration and understanding of the method.

posited, copper is also electrolytically deposited to strengthen the nickel deposit.

The mold with its deposits of nickel and copper is then removed from the bath and the lead mold stripped from the nickel copper plate, which now bears the impression received from the mold and the plate is cut to size and placed in a casting machine.

However, on` the upper or rear surface of the Acopper plate (the nickel face bein-g placed face down in the casting machine) there is always placed a thin sheet of tinfoil to thus tin the copper surface so that when the hot lead, antimony and tin is poured on the plate, it -will adhere thereto, as is well known. In other words, the copper has to be tinned before receiving the base metal.

Due to the great scarcity of tin at the present time, the present invention contemplates dispensing with this coating of tinfoil which had to be from .006 to .008 of an inch thick, and in turn contemplates a further subjecting of the copper nickel plate to a ux hath, so that the base metal will adhere thereto and provide as strong a plate as if the tinfoil were used.

In carrying out my new method, therefore, after the nickel copper plate is removed from its electrolytic bath I clean the same well with hydrochloric acid (HC1) and then wash the same with water.

After the plate is thoroughly cleaned and dried, it is again placed in a ux bath consisting of eight parts of water to one part of zinc chloride (ZnCw-that is, to each pint of water (H2O) I add 59.15 grams of zinc chloride. To this I add a small precent of a wetting agent, such as Aerosol plus one percent of orthophosphoric acid (HsPOl).

'I'he wetting agent permits the bath to flow freely over the copper surface and thus prevent air bubbles. the zinc chloride acts as. the main flux agent and the ortho-phosphoric a'cid prevents the lead of the base metal from blistering so that there is a perfect adhesion between the copper and the base metal.

Thus the washing of the copper nickel plate in the above mentioned bath properly conditions the copper surface for the molten base metal that is to be poured thereon.

After the plate has thus been properly washed and conditioned. the solution is allowed to dry and evaporate from the copper surface, after which the hot base metal may be cast thereon.

It will be understood that in some instances I may dispense with the wetting agent, but its addition seems to add to the emciency of the flux bath. Y

It will be understood that the proportions I have used have proved the most effective in hundreds of tests but I do not wish to be limited to the exact ilgures set out.

It will also be understood that although the method herein outlined is primarily designed to provide a conditioning of the copper nickel plates of a printing plate for the adherence of the base metal, to wit: an alloy of lead, tin and antimony, it will be seen that this flux bath might be used on various forms oi.' copper plates where it has heretofore been necessary to provide a tinning agent before another metal or alloy is cast thereon.

From the foregoing it will be seen that I have provided a. new and novel method for the formation of the composite printing plates in which I entirely dispense with the tinfoil, and in its place use a conditioning bath that provides as good results as those obtained with the tlnfoil.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

l. The method of conditioning a copper plate for the adherence of an alloy.of lead. tin and antimony which consists in subjecting the plate to a bath consisting of water. vzinc chloride, and ortho-phosphoric acid.

2. The method of conditioning a copper plate for the adherence of an alloy of lead, tin and antimony which consists in subiecting the plate to a bath consisting of water, zinc chloride. a wetting agent and ortho-phosphoric acid.

3. I'he method of conditioning a copper plate for the adherence of an alloy of lead, tin and antimony which consists in subjecting the plate to a bath consisting of one part of zinc chloride to eight parts of water plus a wetting agent and one percent of ortho-phosphoric acid.

4. The method of forming and conditioning a copper nickel printing plate which consists in placing the same in a flux bath consisting of water, zinc chloride, a wetting agent and orthophosphoric acid, and then casting thereon a base metal alloy of lead, antimony and tin.

5. The method of forming printing plates and the like which consists in placing the master plate against a mold, electrolytically depositing nickel and copper on said mold, stripping said mold from the copper nickel plate, washing the plate, submitting the plate to a ilux bath consisting of water, zinc chloride, and ortho-phosphoric acid, drying the same and then casting electrotype metal on said conditioned copper surface.

AXEL E. LUNDBYE. 

